On 10/30/23 04:50, Antoniu Miclaus wrote:
RTC driver for MAX31335 ±2ppm Automotive Real-Time Clock with
Integrated MEMS Resonator.
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
---
drivers/rtc/Kconfig | 11 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-max31335.c | 759 +++++++++++++++++++++++++++++++++++++
3 files changed, 771 insertions(+)
create mode 100644 drivers/rtc/rtc-max31335.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index d7502433c78a..11c7d7fe1e85 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -373,6 +373,17 @@ config RTC_DRV_MAX8997
This driver can also be built as a module. If so, the module
will be called rtc-max8997.
+config RTC_DRV_MAX31335
+ tristate "Analog Devices MAX31335"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ If you say yes here you get support for the Analog Devices
+ MAX31335.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-max31335.
+
config RTC_DRV_MAX77686
tristate "Maxim MAX77686"
depends on MFD_MAX77686 || MFD_MAX77620 || MFD_MAX77714 || COMPILE_TEST
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index fd209883ee2e..99e683a48240 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
obj-$(CONFIG_RTC_DRV_M48T35) += rtc-m48t35.o
obj-$(CONFIG_RTC_DRV_M48T59) += rtc-m48t59.o
obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
+obj-$(CONFIG_RTC_DRV_MAX31335) += rtc-max31335.o
obj-$(CONFIG_RTC_DRV_MAX6900) += rtc-max6900.o
obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
obj-$(CONFIG_RTC_DRV_MAX6916) += rtc-max6916.o
diff --git a/drivers/rtc/rtc-max31335.c b/drivers/rtc/rtc-max31335.c
new file mode 100644
index 000000000000..159a019524b1
--- /dev/null
+++ b/drivers/rtc/rtc-max31335.c
@@ -0,0 +1,759 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC driver for the MAX31335
+ *
+ * Copyright (C) 2023 Analog Devices
+ *
+ * Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
+ *
+ */
+
+#include <asm-generic/unaligned.h>
+#include <linux/bcd.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/util_macros.h>
+
+/* MAX31335 Register Map */
+#define MAX31335_STATUS1 0x00
+#define MAX31335_INT_EN1 0x01
+#define MAX31335_STATUS2 0x02
+#define MAX31335_INT_EN2 0x03
+#define MAX31335_RTC_RESET 0x04
+#define MAX31335_RTC_CONFIG 0x05
+#define MAX31335_RTC_CONFIG2 0x06
+#define MAX31335_TIMESTAMP_CONFIG 0x07
+#define MAX31335_TIMER_CONFIG 0x08
+#define MAX31335_SECONDS_1_128 0x09
+#define MAX31335_SECONDS 0x0A
+#define MAX31335_MINUTES 0x0B
+#define MAX31335_HOURS 0x0C
+#define MAX31335_DAY 0x0D
+#define MAX31335_DATE 0x0E
+#define MAX31335_MONTH 0x0F
+#define MAX31335_YEAR 0x0F
+#define MAX31335_ALM1_SEC 0x11
+#define MAX31335_ALM1_MIN 0x12
+#define MAX31335_ALM1_HRS 0x13
+#define MAX31335_ALM1_DAY_DATE 0x14
+#define MAX31335_ALM1_MON 0x15
+#define MAX31335_ALM1_YEAR 0x16
+#define MAX31335_ALM2_MIN 0x17
+#define MAX31335_ALM2_HRS 0x18
+#define MAX31335_ALM2_DAY_DATE 0x19
+#define MAX31335_TIMER_COUNT 0x1A
+#define MAX31335_TIMER_INIT 0x1B
+#define MAX31335_PWR_MGMT 0x1C
+#define MAX31335_TRICKLE_REG 0x1D
+#define MAX31335_AGING_OFFSET 0x1E
+#define MAX31335_TS_CONFIG 0x30
+#define MAX31335_TEMP_ALARM_HIGH_MSB 0x31
+#define MAX31335_TEMP_ALARM_HIGH_LSB 0x32
+#define MAX31335_TEMP_ALARM_LOW_MSB 0x33
+#define MAX31335_TEMP_ALARM_LOW_LSB 0x34
+#define MAX31335_TEMP_DATA_MSB 0x35
+#define MAX31335_TEMP_DATA_LSB 0x36
+#define MAX31335_TS0_SEC_1_128 0x40
+#define MAX31335_TS0_SEC 0x41
+#define MAX31335_TS0_MIN 0x42
+#define MAX31335_TS0_HOUR 0x43
+#define MAX31335_TS0_DATE 0x44
+#define MAX31335_TS0_MONTH 0x45
+#define MAX31335_TS0_YEAR 0x46
+#define MAX31335_TS0_FLAGS 0x47
+#define MAX31335_TS1_SEC_1_128 0x48
+#define MAX31335_TS1_SEC 0x49
+#define MAX31335_TS1_MIN 0x4A
+#define MAX31335_TS1_HOUR 0x4B
+#define MAX31335_TS1_DATE 0x4C
+#define MAX31335_TS1_MONTH 0x4D
+#define MAX31335_TS1_YEAR 0x4E
+#define MAX31335_TS1_FLAGS 0x4F
+#define MAX31335_TS2_SEC_1_128 0x50
+#define MAX31335_TS2_SEC 0x51
+#define MAX31335_TS2_MIN 0x52
+#define MAX31335_TS2_HOUR 0x53
+#define MAX31335_TS2_DATE 0x54
+#define MAX31335_TS2_MONTH 0x55
+#define MAX31335_TS2_YEAR 0x56
+#define MAX31335_TS2_FLAGS 0x57
+#define MAX31335_TS3_SEC_1_128 0x58
+#define MAX31335_TS3_SEC 0x59
+#define MAX31335_TS3_MIN 0x5A
+#define MAX31335_TS3_HOUR 0x5B
+#define MAX31335_TS3_DATE 0x5C
+#define MAX31335_TS3_MONTH 0x5D
+#define MAX31335_TS3_YEAR 0x5E
+#define MAX31335_TS3_FLAGS 0x5F
+
+/* MAX31335_STATUS1 Bit Definitions */
+#define MAX31335_STATUS1_PSDECT BIT(7)
+#define MAX31335_STATUS1_OSF BIT(6)
+#define MAX31335_STATUS1_PFAIL BIT(5)
+#define MAX31335_STATUS1_VBATLOW BIT(4)
+#define MAX31335_STATUS1_DIF BIT(3)
+#define MAX31335_STATUS1_TIF BIT(2)
+#define MAX31335_STATUS1_A2F BIT(1)
+#define MAX31335_STATUS1_A1F BIT(0)
+
+/* MAX31335_INT_EN1 Bit Definitions */
+#define MAX31335_INT_EN1_DOSF BIT(6)
+#define MAX31335_INT_EN1_PFAILE BIT(5)
+#define MAX31335_INT_EN1_VBATLOWE BIT(4)
+#define MAX31335_INT_EN1_DIE BIT(3)
+#define MAX31335_INT_EN1_TIE BIT(2)
+#define MAX31335_INT_EN1_A2IE BIT(1)
+#define MAX31335_INT_EN1_A1IE BIT(0)
+
+/* MAX31335_STATUS2 Bit Definitions */
+#define MAX31335_STATUS2_TEMP_RDY BIT(2)
+#define MAX31335_STATUS2_OTF BIT(1)
+#define MAX31335_STATUS2_UTF BIT(0)
+
+/* MAX31335_INT_EN2 Bit Definitions */
+#define MAX31335_INT_EN2_TEMP_RDY_EN BIT(2)
+#define MAX31335_INT_EN2_OTIE BIT(1)
+#define MAX31335_INT_EN2_UTIE BIT(0)
+
+/* MAX31335_RTC_RESET Bit Definitions */
+#define MAX31335_RTC_RESET_SWRST BIT(0)
+
+/* MAX31335_RTC_CONFIG1 Bit Definitions */
+#define MAX31335_RTC_CONFIG1_EN_IO BIT(6)
+#define MAX31335_RTC_CONFIG1_A1AC GENMASK(5, 4)
+#define MAX31335_RTC_CONFIG1_DIP BIT(3)
+#define MAX31335_RTC_CONFIG1_I2C_TIMEOUT BIT(1)
+#define MAX31335_RTC_CONFIG1_EN_OSC BIT(0)
+
+/* MAX31335_RTC_CONFIG2 Bit Definitions */
+#define MAX31335_RTC_CONFIG2_ENCLKO BIT(2)
+#define MAX31335_RTC_CONFIG2_CLKO_HZ GENMASK(1, 0)
+
+/* MAX31335_TIMESTAMP_CONFIG Bit Definitions */
+#define MAX31335_TIMESTAMP_CONFIG_TSVLOW BIT(5)
+#define MAX31335_TIMESTAMP_CONFIG_TSPWM BIT(4)
+#define MAX31335_TIMESTAMP_CONFIG_TSDIN BIT(3)
+#define MAX31335_TIMESTAMP_CONFIG_TSOW BIT(2)
+#define MAX31335_TIMESTAMP_CONFIG_TSR BIT(1)
+#define MAX31335_TIMESTAMP_CONFIG_TSE BIT(0)
+
+/* MAX31335_TIMER_CONFIG Bit Definitions */
+#define MAX31335_TIMER_CONFIG_TE BIT(4)
+#define MAX31335_TIMER_CONFIG_TPAUSE BIT(3)
+#define MAX31335_TIMER_CONFIG_TRPT BIT(2)
+#define MAX31335_TIMER_CONFIG_TFS GENMASK(1, 0)
+
+/* MAX31335_HOURS Bit Definitions */
+#define MAX31335_HOURS_F_24_12 BIT(6)
+#define MAX31335_HOURS_HR_20_AM_PM BIT(5)
+
+/* MAX31335_MONTH Bit Definitions */
+#define MAX31335_MONTH_CENTURY BIT(7)
+
+/* MAX31335_PWR_MGMT Bit Definitions */
+#define MAX31335_PWR_MGMT_PFVT BIT(0)
+
+/* MAX31335_TRICKLE_REG Bit Definitions */
+#define MAX31335_TRICKLE_REG_TRICKLE GENMASK(3, 1)
+#define MAX31335_TRICKLE_REG_EN_TRICKLE BIT(0)
+
+/* MAX31335_TS_CONFIG Bit Definitions */
+#define MAX31335_TS_CONFIG_AUTO BIT(4)
+#define MAX31335_TS_CONFIG_CONVERT_T BIT(3)
+#define MAX31335_TS_CONFIG_TSINT GENMASK(2, 0)
+
+/* MAX31335_TS_FLAGS Bit Definitions */
+#define MAX31335_TS_FLAGS_VLOWF BIT(3)
+#define MAX31335_TS_FLAGS_VBATF BIT(2)
+#define MAX31335_TS_FLAGS_VCCF BIT(1)
+#define MAX31335_TS_FLAGS_DINF BIT(0)
+
+/* MAX31335 Miscellaneous Definitions */
+#define MAX31335_STATUS1_DEFAULT 0x40
+#define MAX31335_RAM_SIZE 32
+#define MAX31335_TIME_SIZE 0x07
+
+#define clk_hw_to_max31335(_hw) container_of(_hw, struct max31335_data, clkout)
+
+struct max31335_data {
+ struct regmap *regmap;
+ struct rtc_device *rtc;
+ struct clk_hw clkout;
+};
+
+static const int max31335_clkout_freq[] = { 1, 64, 1024, 32768 };
+
+static const u16 max31335_trickle_resistors[] = {3000, 6000, 11000};
+
+static bool max31335_volatile_reg(struct device *dev, unsigned int reg)
+{
+ /* time keeping registers */
+ if (reg >= MAX31335_SECONDS &&
+ reg < MAX31335_SECONDS + MAX31335_TIME_SIZE)
+ return true;
+
+ /* interrupt status register */
+ if (reg == MAX31335_INT_EN1_A1IE)
+ return true;
+
+ /* temperature registers */
+ if (reg == MAX31335_TEMP_DATA_MSB || MAX31335_TEMP_DATA_LSB)
+ return true;
+}
+
+static const struct regmap_config regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = 0x5F,
+ .volatile_reg = max31335_volatile_reg,
+};
+
+static int max31335_get_hour(u8 hour_reg)
+{
+ int hour;
+
+ /* 24Hr mode */
+ if (!FIELD_GET(MAX31335_HOURS_F_24_12, hour_reg))
+ return bcd2bin(hour_reg & 0x3f);
+
+ /* 12Hr mode */
+ hour = bcd2bin(hour_reg & 0x1f);
+ if (hour == 12)
+ hour = 0;
+
+ if (FIELD_GET(MAX31335_HOURS_HR_20_AM_PM, hour_reg))
+ hour += 12;
+
+ return hour;
+}
+
+static int max31335_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ u8 date[7];
+ int ret;
+
+ ret = regmap_bulk_read(max31335->regmap, MAX31335_SECONDS, date,
+ sizeof(date));
+ if (ret)
+ return ret;
+
+ tm->tm_sec = bcd2bin(date[0] & 0x7f);
+ tm->tm_min = bcd2bin(date[1] & 0x7f);
+ tm->tm_hour = max31335_get_hour(date[2]);
+ tm->tm_wday = bcd2bin(date[3] & 0x7) - 1;
+ tm->tm_mday = bcd2bin(date[4] & 0x3f);
+ tm->tm_mon = bcd2bin(date[5] & 0x1f) - 1;
+ tm->tm_year = bcd2bin(date[6]) + 100;
+
+ if (FIELD_GET(MAX31335_MONTH_CENTURY, date[5]))
+ tm->tm_year += 100;
+
+ return 0;
+}
+
+static int max31335_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ u8 date[7];
+
+ date[0] = bin2bcd(tm->tm_sec);
+ date[1] = bin2bcd(tm->tm_min);
+ date[2] = bin2bcd(tm->tm_hour);
+ date[3] = bin2bcd(tm->tm_wday + 1);
+ date[4] = bin2bcd(tm->tm_mday);
+ date[5] = bin2bcd(tm->tm_mon + 1);
+ date[6] = bin2bcd(tm->tm_year % 100);
+
+ if (tm->tm_year >= 200)
+ date[5] |= FIELD_PREP(MAX31335_MONTH_CENTURY, 1);
+
+ return regmap_bulk_write(max31335->regmap, MAX31335_SECONDS, date,
+ sizeof(date));
+}
+
+static int max31335_read_offset(struct device *dev, long *offset)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ u32 value;
+ int ret;
+
+ ret = regmap_read(max31335->regmap, MAX31335_AGING_OFFSET, &value);
+ if (ret)
+ return ret;
+
+ *offset = value;
+
+ return 0;
+}
+
+static int max31335_set_offset(struct device *dev, long offset)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+
+ return regmap_write(max31335->regmap, MAX31335_AGING_OFFSET, offset);
+}
+
+static int max31335_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ struct mutex *lock = &max31335->rtc->ops_lock;
+ int ret, ctrl, status;
+ struct rtc_time time;
+ u8 regs[6];
+
+ mutex_lock(lock);
+
+ ret = regmap_bulk_read(max31335->regmap, MAX31335_ALM1_SEC, regs,
+ sizeof(regs));
+ if (ret)
+ goto exit;
+
+ alrm->time.tm_sec = bcd2bin(regs[0] & 0x7f);
+ alrm->time.tm_min = bcd2bin(regs[1] & 0x7f);
+ alrm->time.tm_hour = bcd2bin(regs[2] & 0x3f);
+ alrm->time.tm_mday = bcd2bin(regs[3] & 0x3f);
+ alrm->time.tm_mon = bcd2bin(regs[4] & 0x1f) - 1;
+ alrm->time.tm_year = bcd2bin(regs[5]) + 100;
+
+ ret = max31335_read_time(dev, &time);
+ if (ret)
+ goto exit;
+
+ if (time.tm_year >= 200)
+ alrm->time.tm_year += 100;
+
+ ret = regmap_read(max31335->regmap, MAX31335_INT_EN1, &ctrl);
+ if (ret)
+ goto exit;
+
+ ret = regmap_read(max31335->regmap, MAX31335_STATUS1, &status);
+ if (ret)
+ goto exit;
+
+ alrm->enabled = FIELD_GET(MAX31335_INT_EN1_A1IE, ctrl);
+ alrm->pending = FIELD_GET(MAX31335_STATUS1_A1F, status);
+
+exit:
+ mutex_unlock(lock);
+
+ return ret;
+}
+
+static int max31335_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ struct mutex *lock = &max31335->rtc->ops_lock;
+ unsigned int reg;
+ u8 regs[6];
+ int ret;
+
+ regs[0] = bin2bcd(alrm->time.tm_sec);
+ regs[1] = bin2bcd(alrm->time.tm_min);
+ regs[2] = bin2bcd(alrm->time.tm_hour);
+ regs[3] = bin2bcd(alrm->time.tm_mday);
+ regs[4] = bin2bcd(alrm->time.tm_mon + 1);
+ regs[5] = bin2bcd(alrm->time.tm_year % 100);
+
+ mutex_lock(lock);
+
+ ret = regmap_bulk_write(max31335->regmap, MAX31335_ALM1_SEC,
+ regs, sizeof(regs));
+ if (ret)
+ goto exit;
+
+ reg = FIELD_PREP(MAX31335_INT_EN1_A1IE, alrm->enabled);
+ ret = regmap_update_bits(max31335->regmap, MAX31335_INT_EN1,
+ MAX31335_INT_EN1_A1IE, reg);
+ if (ret)
+ goto exit;
+
+ ret = regmap_update_bits(max31335->regmap, MAX31335_STATUS1,
+ MAX31335_STATUS1_A1F, 0);
+
+exit:
+ mutex_unlock(lock);
+
+ return ret;
+}
+
+static int max31335_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+
+ return regmap_update_bits(max31335->regmap, MAX31335_INT_EN1,
+ MAX31335_INT_EN1_A1IE, enabled);
+}
+
+static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
+{
+ struct max31335_data *max31335 = dev_id;
+ struct mutex *lock = &max31335->rtc->ops_lock;
+ int ret, status;
+
+ mutex_lock(lock);
+
+ ret = regmap_read(max31335->regmap, MAX31335_STATUS1, &status);
+ if (ret)
+ goto exit;
+
+ if (FIELD_GET(MAX31335_STATUS1_A1F, status)) {
+ ret = regmap_update_bits(max31335->regmap, MAX31335_STATUS1,
+ MAX31335_STATUS1_A1F, 0);
+ if (ret)
+ goto exit;
+
+ rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
+ }
+
+exit:
+ mutex_unlock(lock);
+
+ return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops max31335_rtc_ops = {
+ .read_time = max31335_read_time,
+ .set_time = max31335_set_time,
+ .read_offset = max31335_read_offset,
+ .set_offset = max31335_set_offset,
+ .read_alarm = max31335_read_alarm,
+ .set_alarm = max31335_set_alarm,
+ .alarm_irq_enable = max31335_alarm_irq_enable,
+};
+
+static int max31335_trickle_charger_setup(struct device *dev,
+ struct max31335_data *max31335)
+{
+ u32 ohms;
+ bool diode = false;
+ int i;
+
+ if (device_property_read_u32(dev, "trickle-resistor-ohms", &ohms))
+ return 0;
+
+ if (device_property_read_bool(dev, "trickle-diode-enable"))
+ diode = true;
+
diode = device_property_read_bool(dev, "trickle-diode-enable");
+ for (i = 0; i < ARRAY_SIZE(max31335_trickle_resistors); i++)
+ if (ohms == max31335_trickle_resistors[i])
+ break;
+
+ if (i >= ARRAY_SIZE(max31335_trickle_resistors)) {
+ dev_err_probe(dev, -EINVAL, "invalid trickle resistor value\n");
+
Should this return a hard error ? After all, it is a devicetree problem
resulting in a failure to enable trickle charging even though tricke
charging is requested.
+ return 0;
+ }
+
+ if (diode)
+ i = i + 4;
+ else
+ i = i + 1;
+
+ return regmap_write(max31335->regmap, MAX31335_TRICKLE_REG,
+ FIELD_PREP(MAX31335_TRICKLE_REG_TRICKLE, i) |
+ MAX31335_TRICKLE_REG_EN_TRICKLE);
+}
+
+static unsigned long max31335_clkout_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct max31335_data *max31335 = clk_hw_to_max31335(hw);
+ unsigned int freq_mask;
+ unsigned int reg;
+ int ret;
+
+ ret = regmap_read(max31335->regmap, MAX31335_RTC_CONFIG2, ®);
+ if (ret)
+ return 0;
+
+ freq_mask = __roundup_pow_of_two(ARRAY_SIZE(max31335_clkout_freq)) - 1;
+
+ return max31335_clkout_freq[reg & freq_mask];
+}
+
+static long max31335_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ int index;
+
+ index = find_closest(rate, max31335_clkout_freq,
+ ARRAY_SIZE(max31335_clkout_freq));
+
+ return max31335_clkout_freq[index];
+}
+
+static int max31335_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct max31335_data *max31335 = clk_hw_to_max31335(hw);
+ unsigned int freq_mask;
+ int index;
+
+ index = find_closest(rate, max31335_clkout_freq,
+ ARRAY_SIZE(max31335_clkout_freq));
+ freq_mask = __roundup_pow_of_two(ARRAY_SIZE(max31335_clkout_freq)) - 1;
+
+ return regmap_update_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
+ freq_mask, index);
+}
+
+static int max31335_clkout_enable(struct clk_hw *hw)
+{
+ struct max31335_data *max31335 = clk_hw_to_max31335(hw);
+
+ return regmap_set_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
+ MAX31335_RTC_CONFIG2_ENCLKO);
+}
+
+static void max31335_clkout_disable(struct clk_hw *hw)
+{
+ struct max31335_data *max31335 = clk_hw_to_max31335(hw);
+
+ regmap_clear_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
+ MAX31335_RTC_CONFIG2_ENCLKO);
+}
+
+static int max31335_clkout_is_enabled(struct clk_hw *hw)
+{
+ struct max31335_data *max31335 = clk_hw_to_max31335(hw);
+ unsigned int reg;
+ int ret;
+
+ ret = regmap_read(max31335->regmap, MAX31335_RTC_CONFIG2, ®);
+ if (ret)
+ return ret;
+
+ return !!(reg & MAX31335_RTC_CONFIG2_ENCLKO);
+}
+
+static const struct clk_ops max31335_clkout_ops = {
+ .recalc_rate = max31335_clkout_recalc_rate,
+ .round_rate = max31335_clkout_round_rate,
+ .set_rate = max31335_clkout_set_rate,
+ .enable = max31335_clkout_enable,
+ .disable = max31335_clkout_disable,
+ .is_enabled = max31335_clkout_is_enabled,
+};
+
+struct clk_init_data max31335_clk_init = {
+ .name = "max31335-clkout",
+ .ops = &max31335_clkout_ops,
+};
+
+static int max31335_nvmem_reg_read(void *priv, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct max31335_data *max31335 = priv;
+ unsigned int reg = MAX31335_TS0_SEC_1_128 + offset;
+
+ return regmap_bulk_read(max31335->regmap, reg, val, bytes);
+}
+
+static int max31335_nvmem_reg_write(void *priv, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct max31335_data *max31335 = priv;
+ unsigned int reg = MAX31335_TS0_SEC_1_128 + offset;
+
+ return regmap_bulk_write(max31335->regmap, reg, val, bytes);
+}
+
+struct nvmem_config max31335_nvmem_cfg = {
+ .reg_read = max31335_nvmem_reg_read,
+ .reg_write = max31335_nvmem_reg_write,
+ .word_size = 8,
+ .size = MAX31335_RAM_SIZE,
+};
+
+static int max31335_read_temp(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ u8 reg[2];
+ s16 temp;
+ int ret;
+
+ if (type != hwmon_temp || attr != hwmon_temp_input)
+ return -EOPNOTSUPP;
+
+ ret = regmap_bulk_read(max31335->regmap, MAX31335_TEMP_DATA_MSB,
+ reg, 2);
+ if (ret)
+ return ret;
+
+ temp = get_unaligned_be16(reg);
+
+ *val = (temp / 64) * 250;
+
+ return 0;
+}
+
+static umode_t max31335_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type == hwmon_temp && attr == hwmon_temp_input)
+ return 0444;
+
+ return 0;
+}
+
+static const struct hwmon_channel_info *max31335_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops max31335_hwmon_ops = {
+ .is_visible = max31335_is_visible,
+ .read = max31335_read_temp,
+};
+
+static const struct hwmon_chip_info max31335_chip_info = {
+ .ops = &max31335_hwmon_ops,
+ .info = max31335_info,
+};
+
+static int max31335_clkout_register(struct device *dev)
+{
+ struct max31335_data *max31335 = dev_get_drvdata(dev);
+ int ret;
+
+ if (!device_property_present(dev, "#clock-cells"))
+ return 0;
+
+ max31335->clkout.init = &max31335_clk_init;
+
+ ret = devm_clk_hw_register(dev, &max31335->clkout);
+ if (ret)
+ return dev_err_probe(dev, ret, "cannot register clock\n");
+
+ ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
+ &max31335->clkout);
+ if (ret)
+ return dev_err_probe(dev, ret, "cannot add hw provider\n");
+
+ ret = clk_prepare_enable(max31335->clkout.clk);
Should this call devm_clk_get_enabled() ?
+ if (ret)
+ return dev_err_probe(dev, ret, "cannot enable clkout\n");
+
+ return 0;
+}
+
+static int max31335_probe(struct i2c_client *client)
+{
+ struct max31335_data *max31335;
+ struct device *hwmon;
+ int ret, status;
+
+ max31335 = devm_kzalloc(&client->dev, sizeof(struct max31335_data),
+ GFP_KERNEL);
+ if (!max31335)
+ return -ENOMEM;
+
+ max31335->regmap = devm_regmap_init_i2c(client, ®map_config);
+ if (IS_ERR(max31335->regmap))
+ return PTR_ERR(max31335->regmap);
+
+ i2c_set_clientdata(client, max31335);
+
+ ret = regmap_write(max31335->regmap, MAX31335_RTC_RESET, 1);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(max31335->regmap, MAX31335_RTC_RESET, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(max31335->regmap, MAX31335_STATUS1, &status);
+ if (ret)
+ return ret;
+
+ if (status != MAX31335_STATUS1_DEFAULT)
+ dev_err_probe(&client->dev, -EINVAL,
+ "Unable to read from device.\n");
+
That is misleading. The device returned an unexpected status.
I don't know if this really reflects a problem, but it is not
"Unable to read from device".
+ max31335->rtc = devm_rtc_allocate_device(&client->dev);
+ if (IS_ERR(max31335->rtc))
+ return PTR_ERR(max31335->rtc);
+
+ max31335->rtc->ops = &max31335_rtc_ops;
+ max31335->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ max31335->rtc->range_max = RTC_TIMESTAMP_END_2199;
+
+ ret = devm_rtc_register_device(max31335->rtc);
+ if (ret)
+ return ret;
+
+ ret = max31335_clkout_register(&client->dev);
+ if (ret)
+ return ret;
+
+ if (client->irq > 0) {
+ ret = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, max31335_handle_irq,
+ IRQF_ONESHOT,
+ "max31335", max31335);
+ if (ret) {
+ dev_warn(&client->dev,
+ "unable to request IRQ, alarm max31335 disabled\n");
+ client->irq = 0;
+ }
+ }
+
+ if (!client->irq)
+ clear_bit(RTC_FEATURE_ALARM, max31335->rtc->features);
+
+ max31335_nvmem_cfg.priv = max31335;
+ ret = devm_rtc_nvmem_register(max31335->rtc, &max31335_nvmem_cfg);
+ if (ret)
+ dev_err_probe(&client->dev, ret, "cannot register rtc nvmem\n");
+
+ hwmon = devm_hwmon_device_register_with_info(&client->dev, client->name,
+ max31335,
+ &max31335_chip_info,
+ NULL);
+ if (IS_ERR(hwmon))
+ dev_err_probe(&client->dev, PTR_ERR(hwmon),
+ "cannot register hwmon device\n");
+
+ return max31335_trickle_charger_setup(&client->dev, max31335);
+}
+
+static const struct i2c_device_id max31335_id[] = {
+ { "max31335", 0 },
+ { }
+};
+
+MODULE_DEVICE_TABLE(i2c, max31335_id);
+
+static const struct of_device_id max31335_of_match[] = {
+ { .compatible = "adi,max31335" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, max31335_of_match);
+
+static struct i2c_driver max31335_driver = {
+ .driver = {
+ .name = "rtc-max31335",
+ .of_match_table = max31335_of_match,
+ },
+ .probe = max31335_probe,
+ .id_table = max31335_id,
+};
+module_i2c_driver(max31335_driver);
+
+MODULE_AUTHOR("Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX31335 RTC driver");
+MODULE_LICENSE("GPL");
